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1 15325 Pre-work assignment Preparing your conflict scenario (four copies of your scenario must be brought to the workshop) Dear Participant, This letter introduces some pre-course work that is essential for you to complete before arriving at the workshop for the subject Negotiations and Conflict Management: 15325 – in which you are enrolled. The workshop will combine theory and practice in a manner intended to use the wisdom in the room to bring together our thinking about enacting the practices you will learn about. You will bring with you a scenario to work through during the workshop. This letter explains how to write that. 1 The situation (you can give it a title if that helps to frame it for you) Your first task is to identify a situation that is (or in your opinion is) unresolved and has potential to escalate into a matter causing stress, tension, delay or confusion. This may be something at work or in a context where you have the power to take action. You will use fictional names and disguise other facts to ensure confidentiality, but it is essential that this is a real situation – not a hypothetical or fictional one. 2 The Details To enable others to understand the context you will need to describe the following – A The people. Describe each person using the following items – Name – Use a fictional name for each person and do not include more than four others apart from yourself. You can use your own name if you wish or also disguise that as well. General facts about each person – gender, age range, role title, marital status (if relevant) work/life location (if other than yours) Personal characteristics – select at least 5 key words/phrases chosen from the list at the end of this letter Relationship to others in the scenario – boss, subordinate, peer, family member, relative etc. B The context. Type of business or other relevant information to provide a general setting for the moment you will use to describe the unresolved issue. C The event (moment in time). This can be at least partly imagined in that you will need to summarise a lot of information and it might be easier to do so if you write it as conversation even if that has not happened. 2 A sample example written in this way follows. This is a real scenario written by a person who will not be attending the workshop. It took 40 minutes to write. That involved 10 minutes to collect thoughts, select words and frame the setting and then 30 minutes to put it into the words you are reading. The advice is to allow yourself at least this amount of time and also to find a quiet space and time to write your scenario. Example Case Study Title – Where is that space? Setting – a Sydney residential street, in a smallish inner city suburb. There is a main road at one end of the street and a large schoolyard at the other end. At the corner of the street and the main road is a temporary church site whose owners are seeking to extend and develop the site. On the opposite corner is a second hand car yard with the imaginative title of “Junk your Jalopy” (JyJ). Aside from a block of six flats next to the home Eva has lived in for 12 years, all the other residences are single storey homes most built in the first two decades of the 20th century. Most residents have at least one car – often two. Umberto works at JyJ and may be a part owner. He doesn’t live nearby. On a recent occasion Eva, who is reasonably laid back but can be forgetful, was moved to anger by the presence, in the street outside her front door, of a very old and battered panel van that she knew did not belong to any of the residents. It has been there for nearly two weeks and meant that she was parking her car out of sight in a side lane, on land owned by the church. This is not official parking for the street and is often blocked off by the church. Walking to the corner one morning she saw Umberto taking photos of a motorbike and went to raise the issue of the van with him. He is not particularly interested in others’ concerns about the lack of parking and merely wants to make a success of the business. If that means parking extra cars in the street and annoying a few residents he’s opportunistic enough to do so without compunction. Although she is usually fearful of conflict Eva was determined to do something to try and put a stop to JYJ’s habit of parking cars illegally in the residential area. She opened the conversation by asking if Umberto knew anything about the van. He denied all knowledge of it and became quite aggressive (or at least it seemed that way to Eva) about the matter of cars in the street, denying that any were from JyJ, suggesting she talk to the owners of the spare parts yard facing the main road. As Eva tried to ask him to consider the needs and rights of residents, Umberto became ever more inflexible disregarding her issue and suggesting she leave his premises. Although she is quite creative, and has worked for 30 years in a variety of roles Eva is not always able to speak her mind easily, and his denials were not helping. He even began whinging about having to ‘cop the s—t’ for the spare parts yard but resisted the idea of marking his cars so residents could see those parked illegally were not his. 3 As she walked away Eva heard herself say “well if you do nothing about it, then you’ll have to continue copping the s—t, and I hope it hurts”, realising as she did so that she would not be any better off for her efforts. When she got home that night the van was gone – but a different one had arrived within four days. The issue is unresolved. Words to describe the people in your scenario accurate inquisitive empire building adaptable knowledgeable erratic analytical logical fearful of conflict broad in outlook loyal forgetful calm & confident observant frightened of failure caring opportunistic fussy challenging original impatient clever outgoing impulsive competitive outspoken indecisive conscientious perfectionist inflexible conscious of priorities persistent insular consultative persuasive laid back 4 co-operative practical manipulative creative professionally dedicated not interested in others diplomatic Marking Criteria for the Case Study How to get the maximum marks for the case study! For 10 marks – the case study – Accurately uses more than the required number of suggested words to describe the people in the scenario. That is the words used to describe the people are descriptive and placed appropriately to ensure a reader is able to create an informative word picture of each person. The sequence of events is presented in a manner that ensures the current situation, and possible consequences of any future actions, are easily understood by a reader not familiar with the context. Includes enough information to ensure that a stranger does not need to ask additional questions to affirm understanding of the situation as described in the case study. For 8 – 9 marks – the case study – Uses the set minimum number of words. The words are used correctly. The sequence is reasonably ordered, but readers find they need to ask one or two questions about the actual context, order of events. There is less that a sufficient amount of information to ensure that a stranger will quickly understand the nature of issues that remain unresolved. For 5 – 7 – the case study – Uses the set minimum number of words. Not all words are used appropriately in the context, but a stranger is able to gain an impression of the people. The sequence of events – as presented in the case study text – needs some re-ordering in response to questions from other readers to enable them to understand the issues. Strangers will need to seek additional information before they feel able to understand the issue and/or the context. For F = less than 5 – the case study – Uses fewer than the set minimum number of words. They do not add to the information about the people. 5 The sequence of events is unclear and does not represent the issue/s in a manner that can be understood by a stranger. A good deal of additional information is required before a stranger can understand the nature of the issues and context.

What is the numerical relationship of neuroglial cells compared to neurons? Select one: a. Because they are big, one neuroglial cell can serve many neurons so there are about nine neurons for every neuroglial cell. b. There are about an equal number of both; each neuron has a companion neuroglial cell. c. There are about 9 neuroglial cells for every neuron. d. The numbers vary widely from animal to animal and depend on how large the animal is. e. Brain volume is made of approximately two thirds neurons and one third neuroglial cells.

ENGG4020/7020 Systems Safety Engineering Group Assignment 2: System Hazard Analysis Semester 2, 2015 School of Information Technology and Electrical Engineering The University of Queensland Goals: To develop skills in System Hazard Analysis (SHA) and gain experience in use of hazard analysis techniques by application to a realistic case study. To develop skills in written communication, in particular the skills associated with preparing written reports. Deadline: Friday 25 September 2015 at 5pm. Late assignments will attract a penalty of 20% per day. What you have to do (group assignment): Prepare a partial SHA for the AETU system (including operator) based on the given Operational Concept Document and AETU Functional Architecture. Your report should cover the following items: Q1. Partial FMEA: (a) Give a failure mode for each of the 10 components described in the AETU Functional Architecture, including the 3 sub-components of the User Interface. That is, describe one particular way in which the component might fail. Try to select examples that are plausible and could contribute to accidents, either directly or indirectly. Include possible causes in each case, to help illustrate the failure mode. (b) For each of the failure modes from (a), describe a possible system hazard that may arise, and why. Display the results in an FMEA table such as Fig.1 below. Component Example failure mode Possible cause Possible hazard How the failure could lead to the hazard … … … … … Figure 1: Format for FMEA table (Q1) Q2. Partial CHAZOP: For this question you will develop a partial CHAZOP for the “initiate/shutdown signal” data flow from the Timer component to the Power component in the AETU Functional Architecture. For the purposes of this exercise you can assume simple initiate and shutdown signals are sent. [Hint: The data flow attributes are very simple in this case, so not all of the CHAZOP guidewords will need an interpretation.] (a) Give interpretations of each of the following guidewords for the two attributes of the above flow: None, Other Than, Early, Late. Note that individual guidewords may have more than one relevant interpretation. (b) Give a partial CHAZOP table for the above flow, using the format given in Fig.2 below. For each deviation, give examples of what could cause the deviation, and what effect it could have. Under “associated safety requirements” describe requirements that could be imposed on the system to prevent the deviation, detect its occurrence and/or mitigate its consequences. Figure 2: Format for CHAZOP table (Q2) Q3. FTA: Develop a Fault Tree for the top event “engine overstressed”, down to the level of the components in the AETU Functional Architecture. Your Fault Tree should focus on secondary failures of the engine due to use or misuse of the AETU. You can assume that the main ways that the AETU might cause the engine to overstress are because of: unsafe inputs being sent to the FADEC; new inputs being sent too soon after other inputs, causing sudden changes to the engine’s state; or insufficient time being left between shutting down the engine and initiating it again. For example, the tree might have “AETU sends unsafe FADEC inputs” as an intermediate node, but then break this down into possible faults associated with the Communications unit, the Command Interpreter, the Input Panel and/or the Operator. Your fault tree should use short meaningful labels for the Fault Tree nodes, and then give a more detailed explanation in the documentation where necessary. Submission: You must carry out this assignment in your assigned group. Group members are expected to participate equally in the assignment. To ensure marks are allocated fairly according to contribution, each group member will be required to submit an individual peer assessment form, which will be made available on the course Blackboard site immediately after the assignment deadline. This form must be completed in the week after the assignment deadline. The SHA report must be submitted via Blackboard. Submit one copy per group to both “Assignment 2” and “Assignment 2 via TurnItIn” with your group ID in the submission name. You can submit via the “Group Assignment 2” link as many times as you like: the last submission is the one that will be marked. The TurnItIn submission mechanism should only be used for the final assignment, even if it’s slightly after the deadline. The submission is to be a single file containing a composite document incorporating all parts of the SHA. The format of the document should be PDF and should use standard 11 point fonts with at least 2 cm margins on all sides. If the group’s performance has been adversely affected by exceptional circumstances, the group may apply to the Course Coordinator for special consideration. Suitable documentary evidence (such as a doctor’s certificate) should be supplied where appropriate. School Policy on Student Misconduct: You are required to read and understand the School Statement on Misconduct, available on the School’s website at: http://www.itee.uq.edu.au/itee-student-misconduct-including-plagiarism Flow Attribute Guide word Interpretation Possible causes Possible consequences Associated safety requirements … … … … … … … Evaluation and Assessment Criteria: This assignment is worth 25 marks – the breakdown is indicated on the coversheet. The mark counts for 20% of the final mark (out of 100). Individual marks will be adjusted from the group mark using a Peer Assessment Factor calculated from group submissions. Criterion Mark Standard Presentation (4 marks): Readability, layout, structure, spelling, grammar. 4 Highly professional report 3 Consistently high standard of presentation 1-2 Good presentation with some presentation faults 0 Poorly prepared work with major presentation faults Failure mode identification (4 marks): Plausible failure mode identified for each AETU component 3-4 Highly plausible failure modes chosen for each of the components, with clear explanation of how they could arise 1-2 Generally good coverage of failure modes for components, with some omissions and/or lack of clarity 0 Major omissions FMEA (3 marks): Plausible effect noted for each failure mode 3 Good examples of associated hazards for each of the 10 cases 1-2 Good examples for some cases but not for others 0-1 Major deficiencies CHAZOP guideword interpretation (3 marks): Appropriate CHAZOP guidewords chosen, with plausible interpretations 3 Appropriate choice of guidewords & interpretations, giving good coverage of possible deviations for this flow 1-2 Gaps in coverage 0 Major deficiencies CHAZOP (5 marks): Plausible causes & effects are noted for each deviation, and resulting safety requirements are identified 4-5 Good examples of possible causes & effects of deviations, with appropriate system safety requirements clearly identified 2-3 Generally good coverage with some omissions and/or lack of clarity 0-1 Major omissions Fault Tree Analysis (6 marks): Fault tree developed for the given event 6 The fault tree shows good understanding of FTA 4-5 Generally good coverage, with some omissions and/or lack of clarity or generality, or issues with structure 2-3 Big gaps in coverage, or poor structure or documentation 0-1 Major deficiencies

Michael Jordan’s book.. Considering how the ending of the book was written, is it an effective ending? Did the ending surprise you? Why? Why not? Did the ending leave you with unanswered questions? Explain.

Page 1 of 2 Name ________________________ ENGR350-01 Learning Exercise 7: Problem 1 [3 points]: For the circuit below, we want to solve for Vc(t). Assume that for t < 0, switch S1 has been closed long enough for Vc(t) to reach a constant value. The switch S1 opens at t=0. Note that the steady state model for a capacitor is an open circuit (since ?????=?). 1a) Find Vc just before t=0 and also for t. 1b) Find τ for t>0 (after the switch opens). 1c) Find Vc(t) mathematically and graph it for the first 50 milliseconds after the switch opens. Make the graph big enough to clearly show the natural response and steady state response. Page 2 of 2 Problem 2 [7 points]: For the circuit below, we want to calculate iL(t). For t<0, you can assume the voltage source has been at +5V for a long time prior to t=0. At t=0, the voltage source drops to -5V and stays. Note that the steady state model for an inductor is a wire (since ?????=?). 2a) Find the value of iL(t) just prior to t=0. 2b) Find the value of iL(t) for t. 2c) Find the time constant τ. 2d) Write the mathematical expression describing iL(t) for t>0. 2e) Based on 2d, find VL(t) for t>0. 2f) Use nodal analysis to find the differential equation governing iL(t) for this circuit, with circuit values (such as R1, R2, L, V1) in addition to iL(t) and ?????. 2g) In this circuit, R2 is actually modeling the resistive loss within a non-ideal inductor. Calculate the point in time when the power dissipated in R2 is minimum. Hint: first think about the point in time that (iL)2 is minimum, since P=i2R for a resistor. +5 Volts -5 Volts V1

Name: Lab Time: BIO 218 Experiment Paper Rubric (20 points) General Formatting: (2 pts.) • Margins should be 1 inch top, bottom, left, and right. • Font should be 12 point Times New Roman or similar font. • Double-spaced. • Pages numbered. Title page is unnumbered. Next page is numbered at the bottom right corner with a 2 followed by pages 3, 4, and 5. • All sections must be included: Abstract, Introduction, Methods, Results, Discussion, and Literature Cited. • At least 3 pages (double spaced) but no more than five pages long. • All scientific names should be formatted correctly by italicizing and capitalizing the genus name and having the species name in lowercase (Bufo americanus). • Title page should have a specific title, student name, course, lab section time, and date. Project elements (18 pts. Total) • Abstract (2 points) o Summarize most important points using past tense. Use present tense to suggest a general conclusion which supports or refutes the hypothesis. • Introduction (3 points) o General background on topic and species (state scientific name!) o Discuss the possible tests of the hypothesis. o Reads from general to specific. o States hypothesis/hypotheses to be addressed. May discuss null and all alternative hypotheses. • Methods (2 points) o Reports how experiment was conducted and all materials used. Use enough detail so others could repeat the study. o Discuss the type(s) of data collected. o Discuss how data was to be analyzed/compared/used to test hypothesis. • Results (3 points) o Reports what happened in the experiment. o If comparisons made, discuss how they were made. o Report statistical and other data. Use “significant” only for statistical significance. o NO interpretation of data (no data analysis). o At least one original figure present and formatted correctly. Figures such as pictures and graphs are numbered and have captions underneath. o At least one table present and formatted correctly. Tables such as charts are numbered and have captions above them. • Discussion: (3 points) o Discusses the results of the experiment and ties in how the results fit with the literature. o Use past tense to discuss your results and shift to present tense to discuss previously published information. o States how results supported or refuted the original hypothesis. Hypotheses are never proven! o Ties in results with big picture within topic of biology. • Literature Cited: (2 points: .5 per citation) o At least 2 peer-reviewed journal articles (provided) + 2 peer-reviewed journal articles (found on your own). o References used in text properly. o References all listed in this section are alphabetized by author’s last name and formatted correctly. o All references listed in the Literature Cited section are cited in text. Writing Elements (3 pts.) • Grammar or spelling is error-free and excellent print quality. (1 pt) • Writing is clear and flows logically throughout paper. (1 pt) • Appropriate content in each section? (1 pt) Additional Comments:

Assignment 7 Due: 11:59pm on Friday, March 21, 2014 You will receive no credit for items you complete after the assignment is due. Grading Policy Conceptual Question 8.5 The figure shows two balls of equal mass moving in vertical circles. Part A Is the tension in string A greater than, less than, or equal to the tension in string B if the balls travel over the top of the circle with equal speed? ANSWER: Correct The tension in string A is less than the tension in string B. The tension in string A is equal to the tension in string B. The tension in string A is greater than the tension in string B. Part B Is the tension in string A greater than, less than, or equal to the tension in string B if the balls travel over the top of the circle with equal angular velocity? ANSWER: Correct A Mass on a Turntable: Conceptual A small metal cylinder rests on a circular turntable that is rotating at a constant rate, as illustrated in the diagram. Part A Which of the following sets of vectors best describes the velocity, acceleration, and net force acting on the cylinder at the point indicated in the diagram? The tension in string A is less than the tension in string B. The tension in string A is equal to the tension in string B. The tension in string A is greater than the tension in string B. Typesetting math: 100% Hint 1. The direction of acceleration can be determined from Newton’s second law According to Newton’s second law, the acceleration of an object has the same direction as the net force acting on that object. ANSWER: Correct Part B Let be the distance between the cylinder and the center of the turntable. Now assume that the cylinder is moved to a new location from the center of the turntable. Which of the following statements accurately describe the motion of the cylinder at the new location? Check all that apply. a b c d e R R/2 Typesetting math: 100% Hint 1. Find the speed of the cylinder Find the speed of the cylinder at the new location. Assume that the cylinder makes one complete turn in a period of time . Express your answer in terms of and . ANSWER: Hint 2. Find the acceleration of the cylinder Find the magnitude of the acceleration of the cylinder at the new location. Assume that the cylinder makes one complete turn in a period of time . Express your answer in terms of and . Hint 1. Centripetal acceleration Recall that the acceleration of an object that moves in a circular path of radius with constant speed has magnitude given by . Note that both the velocity and radius of the trajectory change when the cylinder is moved. ANSWER: ANSWER: v T R T v = R T a T R T r v a = v2 r a = 22R T 2 Typesetting math: 100% Correct Accelerating along a Racetrack A road race is taking place along the track shown in the figure . All of the cars are moving at constant speeds. The car at point F is traveling along a straight section of the track, whereas all the other cars are moving along curved segments of the track. Part A Let be the velocity of the car at point A. What can you say about the acceleration of the car at that point? Hint 1. Acceleration along a curved path The speed of the cylinder has decreased. The speed of the cylinder has increased. The magnitude of the acceleration of the cylinder has decreased. The magnitude of the acceleration of the cylinder has increased. The speed and the acceleration of the cylinder have not changed. v A Typesetting math: 100% Since acceleration is a vector quantity, an object moving at constant speed along a curved path has nonzero acceleration because the direction of its velocity is changing, even though the magnitude of its velocity (the speed) is constant. Moreover, if the speed is constant, the object’s acceleration is always perpendicular to the velocity vector at each point along the curved path and is directed toward the center of curvature of the path. ANSWER: Correct Part B Let be the velocity of the car at point C. What can you say about the acceleration of the car at that point? Hint 1. Acceleration along a curved path Since acceleration is a vector quantity, an object moving at constant speed along a curved path has nonzero acceleration because the direction of its velocity is changing, even though the magnitude of its velocity (the speed) is constant. Moreover, if the speed is constant, the object’s acceleration is always perpendicular to the velocity vector at each point along the curved path and is directed toward the center of curvature of the path. ANSWER: v v The acceleration is parallel to . The acceleration is perpendicular to and directed toward the inside of the track. The acceleration is perpendicular to and directed toward the outside of the track. The acceleration is neither parallel nor perpendicular to . The acceleration is zero. v A v A v A v A v C v v Typesetting math: 100% Correct Part C Let be the velocity of the car at point D. What can you say about the acceleration of the car at that point? Hint 1. Acceleration along a curved path Since acceleration is a vector quantity, an object moving at constant speed along a curved path has nonzero acceleration because the direction of its velocity is changing, even though the magnitude of its velocity (the speed) is constant. Moreover, if the speed is constant, the object’s acceleration is always perpendicular to the velocity vector at each point along the curved path and is directed toward the center of curvature of the path. ANSWER: Correct The acceleration is parallel to . The acceleration is perpendicular to and pointed toward the inside of the track. The acceleration is perpendicular to and pointed toward the outside of the track. The acceleration is neither parallel nor perpendicular to . The acceleration is zero. v C v C v C v C v D v v The acceleration is parallel to . The acceleration is perpendicular to and pointed toward the inside of the track. The acceleration is perpendicular to and pointed toward the outside of the track. The acceleration is neither parallel nor perpendicular to . The acceleration is zero. v D v D v D v D Typesetting math: 100% Part D Let be the velocity of the car at point F. What can you say about the acceleration of the car at that point? Hint 1. Acceleration along a straight path The velocity of an object that moves along a straight path is always parallel to the direction of the path, and the object has a nonzero acceleration only if the magnitude of its velocity changes in time. ANSWER: Correct Part E Assuming that all cars have equal speeds, which car has the acceleration of the greatest magnitude, and which one has the acceleration of the least magnitude? Use A for the car at point A, B for the car at point B, and so on. Express your answer as the name the car that has the greatest magnitude of acceleration followed by the car with the least magnitude of accelation, and separate your answers with a comma. Hint 1. How to approach the problem Recall that the magnitude of the acceleration of an object that moves at constant speed along a curved path is inversely proportional to the radius of curvature of the path. ANSWER: v F The acceleration is parallel to . The acceleration is perpendicular to and pointed toward the inside of the track. The acceleration is perpendicular to and pointed toward the outside of the track. The acceleration is neither parallel nor perpendicular to . The acceleration is zero. v F v F v F v F Typesetting math: 100% Correct Part F Assume that the car at point A and the one at point E are traveling along circular paths that have the same radius. If the car at point A now moves twice as fast as the car at point E, how is the magnitude of its acceleration related to that of car E. Hint 1. Find the acceleration of the car at point E Let be the radius of the two curves along which the cars at points A and E are traveling. What is the magnitude of the acceleration of the car at point E? Express your answer in terms of the radius of curvature and the speed of car E. Hint 1. Uniform circular motion The magnitude of the acceleration of an object that moves with constant speed along a circular path of radius is given by . ANSWER: Hint 2. Find the acceleration of the car at point A If , what is the acceleration of the car at point A? Let be the radius of the two curves along which the cars at points A and E are traveling. Express your answer in terms of the speed of the car at E and the radius . r aE r vE a v r a = v2 r aE = vE 2 r vA = 2vE aA r vE r Typesetting math: 100% Hint 1. Uniform circular motion The magnitude of the acceleration of an object that moves with constant speed along a circular path of radius is given by . ANSWER: ANSWER: Correct Problem 8.5 A 1300 car takes a 50- -radius unbanked curve at 13 . Part A What is the size of the friction force on the car? Express your answer to two significant figures and include the appropriate units. ANSWER: v r a = v2 r aA = 4vE 2 r The magnitude of the acceleration of the car at point A is twice that of the car at point E. The magnitude of the acceleration of the car at point A is the same as that of the car at point E. The magnitude of the acceleration of the car at point A is half that of the car at point E. The magnitude of the acceleration of the car at point A is four times that of the car at point E. kg m m/s Typesetting math: 100% Correct Problem 8.10 It is proposed that future space stations create an artificial gravity by rotating. Suppose a space station is constructed as a 1600- -diameter cylinder that rotates about its axis. The inside surface is the deck of the space station. Part A What rotation period will provide “normal” gravity? Express your answer with the appropriate units. ANSWER: Correct Problem 8.7 In the Bohr model of the hydrogen atom, an electron orbits a proton at a distance of . The proton pulls on the electron with an electric force of . Part A How many revolutions per second does the electron make? Express your answer with the appropriate units. ANSWER: fs = 4400 N m T = 56.8 s (mass m = 9.1 × 10−31 kg) 5.3 × 10−11 m 8.2 × 10−8 N Typesetting math: 100% Correct Problem 8.14 The weight of passengers on a roller coaster increases by 56 as the car goes through a dip with a 38 radius of curvature. Part A What is the car’s speed at the bottom of the dip? Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Problem 8.18 While at the county fair, you decide to ride the Ferris wheel. Having eaten too many candy apples and elephant ears, you find the motion somewhat unpleasant. To take your mind off your stomach, you wonder about the motion of the ride. You estimate the radius of the big wheel to be 14 , and you use your watch to find that each loop around takes 24 . Part A What is your speed? Express your answer to two significant figures and include the appropriate units. ANSWER: 6.56×1015 rev s % m v = 14 ms m s v = 3.7 ms Typesetting math: 100% Correct Part B What is the magnitude of your acceleration? Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Part C What is the ratio of your weight at the top of the ride to your weight while standing on the ground? Express your answer using two significant figures. ANSWER: Correct Part D What is the ratio of your weight at the bottom of the ride to your weight while standing on the ground? Express your answer using two significant figures. ANSWER: a = 0.96 m s2 = 0.90 wtop FG Typesetting math: 100% Correct Enhanced EOC: Problem 8.46 A heavy ball with a weight of 120 is hung from the ceiling of a lecture hall on a 4.4- -long rope. The ball is pulled to one side and released to swing as a pendulum, reaching a speed of 5.6 as it passes through the lowest point. You may want to review ( pages 201 – 204) . For help with math skills, you may want to review: Solutions of Systems of Equations Part A What is the tension in the rope at that point? Express your answer to two significant figures and include the appropriate units. Hint 1. How to approach the problem Start by drawing a free-body diagram indicating the forces acting on the ball when it is at its lowest point. Choose a coordinate system. What is the direction of the acceleration in your chosen coordinate system? What is the magnitude of the acceleration for the mass, which is moving in a circular path? What is Newton’s second law applied to the mass at the bottom of its swing? Make sure to use your coordinate system when determining the signs of all the forces and the acceleration. What is the tension in the rope at this point? ANSWER: = 1.1 wbottom FG N m m/s T = 210 N Typesetting math: 100% Correct Problem 8.43 In an amusement park ride called The Roundup, passengers stand inside a 16.0 -diameter rotating ring. After the ring has acquired sufficient speed, it tilts into a vertical plane, as shown in the figure . Part A Suppose the ring rotates once every 4.80 . If a rider’s mass is 54.0 , with how much force does the ring push on her at the top of the ride? Express your answer with the appropriate units. ANSWER: Correct Part B m s kg 211 N Typesetting math: 100% Suppose the ring rotates once every 4.80 . If a rider’s mass is 54.0 , with how much force does the ring push on her at the bottom of the ride? Express your answer with the appropriate units. ANSWER: Correct Part C What is the longest rotation period of the wheel that will prevent the riders from falling off at the top? Express your answer with the appropriate units. ANSWER: Correct Conceptual Question 9.9 A 2 object is moving to the right with a speed of 1 when it experiences an impulse of 6 . Part A What is the object’s speed after the impulse? Express your answer as an integer and include the appropriate units. ANSWER: s kg 1270 N 5.68 s kg m/s i ^ Ns i ^ v = 4 ms Typesetting math: 100% Correct Part B What is the object’s direction after the impulse? ANSWER: Correct Conceptual Question 9.10 A 2 object is moving to the right with a speed of 2 when it experiences an impulse of -6 . Part A What is the object’s speed after the impulse? Express your answer as an integer and include the appropriate units. ANSWER: Correct Part B What is the object’s direction after the impulse? to the right to the left kg m/s i ^ Ns i ^ v = 1 ms Typesetting math: 100% ANSWER: Correct Problem 9.5 Part A In the figure , what value of gives an impulse of 6.4 ? Express your answer to two significant figures and include the appropriate units. ANSWER: Correct to the right to the left Fmax Ns Fmax = 1.6×103 N Typesetting math: 100% Impulse on a Baseball Learning Goal: To understand the relationship between force, impulse, and momentum. The effect of a net force acting on an object is related both to the force and to the total time the force acts on the object. The physical quantity impulse is a measure of both these effects. For a constant net force, the impulse is given by . The impulse is a vector pointing in the same direction as the force vector. The units of are or . Recall that when a net force acts on an object, the object will accelerate, causing a change in its velocity. Hence the object’s momentum ( ) will also change. The impulse-momentum theorem describes the effect that an impulse has on an object’s motion: . So the change in momentum of an object equals the net impulse, that is, the net force multiplied by the time over which the force acts. A given change in momentum can result from a large force over a short time or a smaller force over a longer time. In Parts A, B, C consider the following situation. In a baseball game the batter swings and gets a good solid hit. His swing applies a force of 12,000 to the ball for a time of . Part A Assuming that this force is constant, what is the magnitude of the impulse on the ball? Enter your answer numerically in newton seconds using two significant figures. ANSWER: Correct We often visualize the impulse by drawing a graph of force versus time. For a constant net force such as that used in the previous part, the graph will look like the one shown in the figure. (F J J = F) t J N * s kg * m/s p = mv )p = J = F) t N 0.70 × 10−3 s J J = 8.4 N * s Typesetting math: 100% Part B The net force versus time graph has a rectangular shape. Often in physics geometric properties of graphs have physical meaning. ANSWER: Correct The assumption of a constant net force is idealized to make the problem easier to solve. A real force, especially in a case like the one presented in Parts A and B, where a large force is applied for a short time, is not likely to be constant. A more realistic graph of the force that the swinging bat applies to the baseball will show the force building up to a maximum value as the bat comes into full contact with the ball. Then as the ball loses contact with the bat, the graph will show the force decaying to zero. It will look like the graph in the figure. For this graph, the length height area slope of the rectangle corresponds to the impulse. Typesetting math: 100% Part C If both the graph representing the constant net force and the graph representing the variable net force represent the same impulse acting on the baseball, which geometric properties must the two graphs have in common? ANSWER: maximum force area slope Typesetting math: 100% Correct When the net force varies over time, as in the case of the real net force acting on the baseball, you can simplify the problem by finding the average net force acting on the baseball during time . This average net force is treated as a constant force that acts on the ball for time . The impulse on the ball can then be found as . Graphically, this method states that the impulse of the baseball can be represented by either the area under the net force versus time curve or the area under the average net force versus time curve. These areas are represented in the figure as the areas shaded in red and blue respectively. The impulse of an object is also related to its change in momentum. Once the impulse is known, it can be used to find the change in momentum, or if either the initial or final momentum is known, the other momentum can be found. Keep in mind that . Because both impulse and momentum are vectors, it is essential to account for the direction of each vector, even in a one-dimensional problem. Part D Assume that a pitcher throws a baseball so that it travels in a straight line parallel to the ground. The batter then hits the ball so it goes directly back to the pitcher along the same straight line. Define the direction the pitcher originally throws the ball as the +x direction. ANSWER: F avg )t )t J = F )t avg J = )p = m(vf − vi ) Typesetting math: 100% Correct Part E Now assume that the pitcher in Part D throws a 0.145- baseball parallel to the ground with a speed of 32 in the +x direction. The batter then hits the ball so it goes directly back to the pitcher along the same straight line. What is the ball’s velocity just after leaving the bat if the bat applies an impulse of to the baseball? Enter your answer numerically in meters per second using two significant figures. ANSWER: Correct The negative sign in the answer indicates that after the bat hits the ball, the ball travels in the opposite direction to that defined to be positive. Problem 9.9 A 2.6 object is moving to the right with a speed of 1.0 when it experiences the force shown in the figure. The impulse on the ball caused by the bat will be in the positive negative x direction. kg m/s −8.4 N * s v = -26 m/s kg m/s Typesetting math: 100% Part A What is the object’s speed after the force ends? Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Part B What is the object’s direction after the force ends? ANSWER: Correct Enhanced EOC: Problem 9.27 A tennis player swings her 1000 g racket with a speed of 11.0 . She hits a 60 g tennis ball that was approaching her at a speed of 19.0 . The ball rebounds at 41.0 . You may want to review ( pages 226 – 232) . For help with math skills, you may want to review: v = 0.62 ms to the right to the left m/s m/s m/s Typesetting math: 100% Solving Algebraic Equations Part A How fast is her racket moving immediately after the impact? You can ignore the interaction of the racket with her hand for the brief duration of the collision. Express your answer with the appropriate units. Hint 1. How to approach the problem Given that you can ignore the interaction of the racket with her hand during the collision, what is conserved during the collision? Draw a picture indicating the direction of the racket and ball before the collision and a separate picture for after the collision. Place a coordinate system on your pictures, indicating the positive x direction. Keeping in mind that velocity can be either positive or negative in your coordinate system, what is the initial momentum of the ball–racket system? What is the final momentum of the ball–racket system in terms of the velocity of the racket after the collision? Using conservation of momentum, what are the velocity and speed of the racket after the collision? ANSWER: Correct Part B If the tennis ball and racket are in contact for 8.00 , what is the average force that the racket exerts on the ball? Express your answer with the appropriate units. Hint 1. How to approach the problem How is the impulse on the ball related to the change in momentum of the ball? What is the change in momentum of the ball? How are the impulse on the ball and the collision time related to the average force on the ball? 7.40 ms ms Typesetting math: 100% ANSWER: Correct Problem 9.14 A 2.00×104 railroad car is rolling at 6.00 when a 6000 load of gravel is suddenly dropped in. Part A What is the car’s speed just after the gravel is loaded? Express your answer with the appropriate units. ANSWER: Correct Problem 9.17 A 330 bird flying along at 5.0 sees a 9.0 insect heading straight toward it with a speed of 34 (as measured by an observer on the ground, not by the bird). The bird opens its mouth wide and enjoys a nice lunch. Part A What is the bird’s speed immediately after swallowing? Express your answer to two significant figures and include the appropriate units. ANSWER: 450 N kg m/s kg 4.62 ms g m/s g m/s Typesetting math: 100% Correct Problem 9.20 A 50.0 archer, standing on frictionless ice, shoots a 200 arrow at a speed of 200 . Part A What is the recoil speed of the archer? Express your answer with the appropriate units. ANSWER: Correct Problem 9.25 A 40.0 ball of clay traveling east at 4.50 collides and sticks together with a 50.0 ball of clay traveling north at 4.50 . Part A What is the speed of the resulting ball of clay? Express your answer with the appropriate units. ANSWER: v = 4.0 ms kg g m/s 0.800 ms g m/s g m/s 3.20 ms Typesetting math: 100% Correct Problem 9.32 A particle of mass is at rest at . Its momentum for is given by , where is in . Part A Find an expression for , the force exerted on the particle as a function of time. Express your answer in terms of the given quantities. ANSWER: Correct Problem 9.37 Most geologists believe that the dinosaurs became extinct 65 million years ago when a large comet or asteroid struck the earth, throwing up so much dust that the sun was blocked out for a period of many months. Suppose an asteroid with a diameter of 2.0 and a mass of 1.2×1013 hits the earth with an impact speed of 4.5×104 . Part A What is the earth’s recoil speed after such a collision? (Use a reference frame in which the earth was initially at rest.) Assume that . Express your answer to two significant figures and include the appropriate units. ANSWER: m t = 0 t > 0 px = 6t2 kgm/s t s Fx(t) Fx = 12t N km kg m/s MEarth= 5.98 × 1024 kg = 9.0×10−8 v ms Typesetting math: 100% Correct Part B What percentage is this of the earth’s speed around the sun? (Use the astronomical data in the textbook.) Express your answer using two significant figures. ANSWER: Correct Problem 9.42 One billiard ball is shot east at 1.8 . A second, identical billiard ball is shot west at 1.2 . The balls have a glancing collision, not a head-on collision, deflecting the second ball by 90 and sending it north at 1.50 . Part A What is the speed of the first ball after the collision? Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Part B What is the direction of the first ball after the collision? Give the direction as an angle south of east. = 3.0×10−10 of v % the earth’s speed m/s m/s 1 m/s v = 1.6 ms Typesetting math: 100% Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Problem 9.49 Two 490 blocks of wood are 2.0 apart on a frictionless table. A 12 bullet is fired at 420 toward the blocks. It passes all the way through the first block, then embeds itself in the second block. The speed of the first block immediately afterward is 5.6 . Part A What is the speed of the second block after the bullet stops? Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Score Summary: Your score on this assignment is 99.5%. You received 156.21 out of a possible total of 157 points. = 68 1 g m g m/s m/s v = 4.6 ms Typesetting math: 100%